If it's mined anywhere in quantity, it's reasonably safe to safe to say that it's mined in Australia. Iron ore, coal, bauxite, uranium, silver, gold, lead, zinc, nickel, diamonds etc etc etc, they're all mined here in huge quantities - this is an incredibly mineral rich country. The pay is usually excellent, but that's mainly because this is a huge country and the mines are hundreds, if not thousands of kilometres away from a decent sized city and good pay is necessary to attract good workers.
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The pay depends on the mine, its location, your skills, how many days you work at a stretch, whether it's FIFO or near a town etc etc. We hear of figures between 100k and more than 200k but that's as close an estimate you be able to get on here. You can be pretty well guaranteed though that there won't be much to spend your money on except booze - most mines are in very remote locations.